by how » Sat Mar 17, 2012 6:05 pm
You will have a legend inside your furnace (probably inside on the door) that lists what code 31 is for Payne.
Tell us what that is. If it's a pressure switch code, then it could be ID motor, capaciter, PS switch or board, all of which do badly when sprayed with water. A pro will have the manometer and HVAC meter to determine what is damaged.